This project examines the cognitive and neural basis of impulsive preference reversal. Human decision-makers sometimes abandon long run outcomes without achieving them. This tendency signals impulsivity, and is an obstacle to the fulfillment of goals involving scholastic success, retirement savings, and recovery from addiction. This work focuses on the distinction between situations where high persistence is warranted and situations where it is beneficial to be less patient. The first aim is to develop a behavioral task to test an individual's ability to adjust his or her level of persistence (upward or downward) to fit the requirements of a situation. Results will be used to inform a model of the underlying cognitive mechanisms. The second aim is to study the neural basis of these adjustments in persistence. Past evidence implicates the ventromedial prefrontal cortex in related functions of value representation, impulsivity, and time perception. Functional magnetic resonance imaging will be used to assess neural engagement while participants perform the same simple task under conditions that either require high persistence or require frequent reversals. In addition, neuropsychological patients with frontal brain lesions will be tested behaviorally; observed patterns of deficit will be informative regarding the computational functions of the affected neural regions. This research will provide a better understanding of the cognitive and neural mechanisms through which people establish an appropriate level of persistence to achieve their long run goals.